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Author Topic: Flywheel  (Read 508 times)

Forumsdwarf

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Flywheel
« on: January 30, 2008, 06:21:00 pm »

A flywheel stores surplus power when a power system is up then releases it when the system goes down.  Multiple flywheels would merge together into one big virtual flywheel.  Flywheels would cost power to keep them spinning.

A flywheel eats whatever surplus power is available in a system when it is in "deficit", that is not fully spun up.  A flywheel releases exactly enough power to keep all devices operational while the system is in deficit.  You might set a minimum operational power level as a percentage of flywheel capacity to simulate the uselessness of devices turning too slowly.

While we're building flywheels it might also be cool to have a ratchet or pawl.  That's a special axle (or axle attachment) that communicates power in only one direction.  For game purposes it would have to communicate power from only one side.  If a water wheel went down a ratchet between it and a flywheel would let the water wheel stop so the flywheel wouldn't waste power on it.

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Draco18s

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Re: Flywheel
« Reply #1 on: January 30, 2008, 10:56:00 pm »

Seconded.
Would be great for waterwheel systems.
I think each flywheel would act like a power system between 2 power systems in the game instead of the way they're supposed to, this is for ease-of-power transfer.

On the input side it causes a 10 power worth of drain on the system per flywheel size (size being equal to how much weight you put on it, which is selected at creation--number of stones or whatever).  The flywheel then outputs the same power as it's recieving as input (minus it's own drain).  Then each (however long) it adds its drain to its reserve--provided that input > output requirement.  If output requirement is > input, then subtract from storage the difference (the flywheel's drain value is lost, as it's putting into the reserve excess power, and even when it's pushing power into the system it's still calculating its drain on the system).

Each flywheel size/segment should be able to store 1000 power, maybe as much as 3000.  This is so that they are still useful in the smallest size when attached to a single waterwheel.  A flywheel at maximum spin should have 0 drain on the system.

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Forumsdwarf

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Re: Flywheel
« Reply #2 on: January 31, 2008, 01:19:00 am »

An axle costs 1 and you're going to make flywheels turn for free?
Geez, we could just use flywheels in place of axles and have zero loss power transfer all over the fort.

Flywheels cost power.  They move air around, there's friction in the bearings that support their weight, and there's probably even some power lost to gyroscopic precess induced by the Earth's rotation.

It wouldn't be hard to make flywheels work realistically.  If a system has surplus power the flywheel takes it all, up to its capacity.  If a system goes into power deficit the flywheel releases as much as needed until it runs out.  If you add a "minimum operational power percentage" below which devices stopped working in a flywheel-attached system that would simulate the low-RPM condition.  You could even display "%RPM" when viewing a flywheel, with 100% RPM meaning the flywheel was fully spun up.  (Displaying RPM as a percent of full speed allows the same calculation if multiple flywheels are in the system, assuming multiple flywheels are merged into 1 big virtual flywheel.)

I do like your ideas of setting the energy capacity of a flywheel when you build it and of its requiring stones for weight.  Cool ideas both.  It should also require a block for mounting and no "hanging" allowed, as it will be heavy.

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Earthquake Damage

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Re: Flywheel
« Reply #3 on: January 31, 2008, 03:07:00 am »

So we could basically use flywheels to prevent power stutters when our water flow isn't smooth?
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Draco18s

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Re: Flywheel
« Reply #4 on: January 31, 2008, 04:54:00 am »

quote:
Originally posted by Forumsdwarf:
<STRONG>An axle costs 1 and you're going to make flywheels turn for free?</STRONG>

Maybe 0 power when fully spun up isn't right, I agree.  I meant it more in terms of "should cost less when fully spinning" as it's not "eating" power any more.  Would be the same as an axle for the space it covers.

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Armok

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Re: Flywheel
« Reply #5 on: January 31, 2008, 03:21:00 pm »

Seconded.
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Sowelu

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Re: Flywheel
« Reply #6 on: January 31, 2008, 06:52:00 pm »

Maybe I'm misunderstanding flywheels, but wouldn't a primative one just add a certain amount of 'inertia' to the power system?  If you hook up a flywheel that spins at, say, 100RPM, then it seems like the whole system would slow down until the flywheel is up to speed.  Once the power source is taken off, the flywheel will keep going at the same rate but very quickly start slowing down, providing its maximum output only very briefly.

I think the belief here is that a flywheel will keep everything running at full power until it gets drained, but I don't think that's very realistic...unless you have like 3x as much flywheel capacity as you have power requirements, so even once it starts spinning down, you have more power than you need for a while.

You'd need a ton of these to be useful, and they wouldn't last long.  Plus the strain would mean you'd need a lot more metal components (though maybe you should anyway).

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Draco18s

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Re: Flywheel
« Reply #7 on: January 31, 2008, 11:48:00 pm »

quote:
Originally posted by Sowelu:
<STRONG>Maybe I'm misunderstanding flywheels, but wouldn't a primative one just add a certain amount of 'inertia' to the power system?  If you hook up a flywheel that spins at, say, 100RPM, then it seems like the whole system would slow down until the flywheel is up to speed.  Once the power source is taken off, the flywheel will keep going at the same rate but very quickly start slowing down, providing its maximum output only very briefly.</STRONG>

That's pretty much what I was trying to convey.  20 power might not be enough, but too much higher and it'd quickly overwhelm any power source and not have enough power to start the flywheel spinning.

And yes, they'd be pretty short-lived.  I was assuming Toady would make my "20 power per whatever" be "20 power PER FRAME."  Which means that a flywheel could provide enough power to a system for...a RT second? dependant on how much is needed compaired to its 1000-3000 power reserve.

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Forumsdwarf

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Re: Flywheel
« Reply #8 on: February 05, 2008, 04:58:00 am »

quote:
Maybe I'm misunderstanding flywheels, but wouldn't a primative one just add a certain amount of 'inertia' to the power system?

All flywheels, primitive or modern, exist for the sole purpose of storing and releasing inertia, though in gyroscopes the inertial transactions are secondary to the purpose of resisting angular torque.

quote:
If you hook up a flywheel that spins at, say, 100RPM, then it seems like the whole system would slow down until the flywheel is up to speed.

The system would "spin up" based on its total resistance versus the torque of the power source from 0 to its operational RPM.  If the system were already turning and you placed an at-rest flywheel in communication with that system, i.e. "popped the clutch", the system would slow down and speed back up just as you described.  Or something would break.

quote:
Once the power source is taken off, the flywheel will keep going at the same rate but very quickly start slowing down

The flywheel will immediately start slowing down, but very slowly, at least if it's sized appropriately to the task.

quote:
I think the belief here is that a flywheel will keep everything running at full power until it gets drained

Well, yes, if you define "full power" as any RPM within operating tolerances and "drained" that point at which flywheel RPM drops below system-nominal RPM.

quote:
unless you have like 3x as much flywheel capacity as you have power requirements, so even once it starts spinning down, you have more power than you need for a while.

That's exactly how flywheels work, though 3x is a little steep.  Your flywheel basically needs to be big enough in a system that spins fast enough to smooth out fluctuations on the input side to within whatever your tolerances are on the output side.  RPM tolerances for millers are pretty relaxed.
RPM tolerances for record players are so tight the early flywheel-based systems had to have governors and clutches to keep the record spinning at a constant rate regardless of flywheel RPM above nominal.  But we aren't playing records on our millstones, just grinding stuff up with them.

quote:
You'd need a ton of these to be useful, and they wouldn't last long.

You only need 1 if it's axial mass is sufficient, and they last virtually forever.

quote:
Plus the strain would mean you'd need a lot more metal components (though maybe you should anyway).

For water milling rock works just fine.  Remember that you don't have to guess at what a flywheel would need to be: they exist in the real world, in the case of water mills ever since the 11th century.  In some mills the millstones themselves had enough axial mass to act as flywheels.  But not our DF mills, hence our need for flywheels.
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